What changes on Medium?
Medium 12×12 Sudoku drops about a quarter of the starter numbers you saw on Easy. That means more of the puzzle is solved by careful scanning, not by spotting the obvious row/column clues. Don't panic — every Medium puzzle on this site still has exactly one solution, and you can always find it without guessing.
If Medium feels like a big jump from Easy, that is normal. Most kids spend a couple of weeks at Easy before Medium starts to feel comfortable. For a refresher on the basics, the 12×12 Sudoku page has the full rules with worked examples.
Three scanning tricks to try
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Number sweep
Pick one number — say 7. Look at every box on the board and ask "could a 7 go here?" If a box already has a 7, skip it. If a box only has one cell where a 7 could fit, write it in. Repeat for every number.
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Box-fill
Find the fullest box. Whatever numbers are missing usually only fit in one or two places. Fill those, then move to the next-fullest box.
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Sum to 78
Each row, column and box adds to 78. If a row is nearly full and the visible numbers add to 71, the missing number must be 7. A surprisingly useful check on a giant board.
How to spot a forced number
A "forced number" is when only one digit can go in a cell, no matter how you look at it. Spotting them is the main skill on Medium. Here is the order we recommend: check the row, then the column, then the 3×4 box. If that leaves only one legal number, write it in.
On a 12×12, the cell you are looking at sees 11 row peers, 11 column peers and 11 box peers. That is a lot of clues. With Auto Notes turned on, the candidates are already filled in for you, so finding cells with only one candidate is the main trick.
When you place a real number, glance back at every row, column and box that touches it. Cells that had two candidates often drop to one — those are your next moves.
When you get stuck
- ✏️ Turn on Auto Notes — on a 12×12 this is hugely useful
- 🔎 Tap Check to make sure every filled cell is still correct
- 💡 Tap Hint to fill one cell (it counts in your stats, but it is okay!)
- ↻ Tap Undo to go back if a guess turned out wrong
Ready for the next step?
When Medium 12×12 Sudoku puzzles take you under 15 minutes, give Hard 12×12 Sudoku a try. Hard puzzles have a lot fewer givens and you will need every trick from this page plus a few more.
Frequently asked questions
How long should Medium 12×12 take?
Most kids finish a Medium 12×12 in 15 to 25 minutes. If it takes longer, that is fine — use Notes and tap Check whenever you want to make sure you are on track.
Can I switch back to Easy?
Of course — just tap the Easy tab at the top of the board. Your Medium puzzle saves automatically.
Are there fewer starter numbers than classic Medium 9×9?
A bit fewer, in proportion. Because the board is bigger, the puzzle still feels solvable even with more empty cells.
Should I memorise anything?
Not really. Just get used to scanning every row, column and box every time you place a digit. After three or four puzzles, the habit becomes automatic.
Try other sudoku games
Different rules, same friendly board. Pick a sibling puzzle to play next.